>> we measured the g forces, impact forces from the very front of the airplane all of the way to the back, front, cockpit and first class, completely destroyed, not survivable. just behind that but in front of the wing, 12 gs, serious potential for injury but is survivable. and then the middle of the airplane, about 8 gs, moderate potential for injury, survival and then the back, about 6 gs, you would have been fine if you were wearing your seat belt. >> reporter: while no crash is the same, where you seat can often make a difference. five rows with na exit can be critical to getting out fast before smoke and flames turn a survivable crash into a fatal one. but there is another obstacle, cables and wires from inflight entertainment systems. >> all this stuff, although relatively light can be significant in impeding your ability to get out of the aircraft. >> reporter: the average man's head? >> average man's head, yes.